1. Field of the Invention
The present invention relates to a process kit containing a photosensitive drum and processing means arranged around the photosensitive drum as a unit. The process kit can be detachably mounted in the main body of image-forming apparatus.
2. Description of the Prior Art
In a long use of image-forming apparatus, for example, a copying machine employing the well-known electrophotographic process, various maintenance works are required which include exchange of the photosensitive medium, supply or exchange of developer, cleaning of charging wires, and adjustment and repair of functional parts etc. Until now these maintenance works have usually been done by a special service man. However, in order to keep the copying machine always in a good state for operation, there have been proposed some methods which enables the maintenance work to be done without the aid of a special service man. One of the methods is to prepare a process kit by assembling some essential components of the copying apparatus such as corona discharger, developing device and photosensitive drum together into a unit. According to the method, the maintenance can be done by the user himself in a simple manner by replacing the used kit by new one. As a further development of this idea it has been proposed also to prepare different types of process kits which are exchangeably used in one and the same main apparatus according to the purpose for which the user intends to use the apparatus. Obviously this broadens the function of the apparatus because one and the same apparatus can be used for different purposes while changing the type of the process kit from one to another.
Although the use of such easily detachable or exchangeable process kits have many merits in the utility and maintenance of the apparatus, there may be produced some problem in the user's handling of the kit. Such a process kit is usually provided with a driving connection part provided thereon through which the kit is connected to the main body of the copying apparatus and through which the driving force is transmitted to the photosensitive drum from the main body. If the driving connection part is damaged by shock and impact, it is rendered unable to normally transmit the driving force to the photosensitive drum. Thereby the quality of images is reduced. In the worst case, the rotation center of the photosensitive drum is dislocated and rendered eccentric, so that it is no longer possible to obtain sharp and clear images. When the process kit is handled by the user, the possibility of damage is not small. In demounting the kit from the main machine or in carrying it after demounting, the man may strike the driving connection part against any rigid body such as desk, wall, pillar or floor. This is an important problem involved in the use of process kit.